This invention related to vehicle suspensions, and more particularly, to a dust shield for use with a damper.
Dampers, e.g., shock absorbers or struts, for suspension systems in automotive vehicles are well known. Some dampers are provided with a mechanism by which the damper serves as a component of a vehicle leveling system. In such a damper, an air chamber is provided that is operatively connected to a source of pressurized air for increasing or decreasing the air pressure within the chamber. The air chamber can be formed between a dust shield and an air sleeve attached to the damper. The dust shield further protects the damper and its seals from contaminants such as dust, dirt, gravel, and so on. Generally, a dust shield is a molded or formed member including a hollow cylindrical body. The dust shield can be formed of metal or plastic, for example, and is positioned over an upper end of the damper, such as a monotube damper.
The air-adjustable damper is typically attached to the vehicle body by a rubber and steel shear mount. A stud holds the shear mount to the damper by threading onto an end of a piston rod. A rate washer portion of the stud or a bump plate is positioned between the rubber portion of the mount and the dust tube. The rate washer or bump plate contacts the rubber portion of the mount when the damper is fully compressed. The configuration of the rate washer determines the deflection rate of the rubber and steel shear mount. The rate washer also functions to hold the dust tube on the damper.
However, the rate washer or bump plate is a steel part that requires a coating for rust protection and adds unwanted mass to the damper. Also, the rate washer is expensive because the shape requires that the washer be machined. Further, threading the rate washer onto the damper piston rod requires an amount of assembly time.
It would be desirable to provide a damper assembly that overcomes these disadvantages.
One aspect of the present invention provides a dust tube for use with a damper including a tubular member having a hollow cylindrical body portion and a substantially closed end. The closed end includes a contoured rate surface on an outer portion thereof.
Other aspects of the present invention provide a dust tube with the closed end including a central opening. The rate surface extends from the central opening to the hollow cylindrical body portion. The rate surface can include a concave profile. The rate surface can include a contoured portion.
Another aspect of the present invention provides a damper assembly including a telescopic damper having a piston rod extending from a first end. A mount assembly is mounted on the piston rod. A dust tube includes a substantially closed end with the closed end being positioned between the telescopic damper and the mount assembly. The closed end can include an opening for receiving the piston rod and a rate surface for contacting a bumper portion of the mount assembly when the damper assembly contracts.
Other aspects of the present invention provide first and second washer members, the first and second washer members respectively positioned adjacent an inner and an outer surface of the closed end adjacent the central opening. The first and second washer members are spaced apart by a spacer member, the spacer member positioned within the central opening of the closed end. A pair of o-ring seals are respectively disposed between an outer diameter of the piston rod and an inner diameter of the spacer and between an outer diameter of the spacer and an inner diameter of the central opening. The first washer member is positioned to contact a shoulder feature of the piston rod. The mount assembly includes a central cylinder disposed on the piston rod. One end of the central cylinder contacts the second washer member and the other end of the central cylinder contacts a retaining member. A fastener member can secure the retaining member against the central cylinder. The fastener member can be threadably engaged to the piston rod. An elastomeric member can be disposed on the central cylinder. A bumper portion can form a portion of the elastomeric member, the bumper being positioned adjacent the rate surface and being drawn into engagement with the rate surface upon contraction of the assembly. The assembly can include at least a pair of mounting studs provided in the elastomeric portion of the mount assembly. The rate surface can be a contoured surface. The rate surface can be a concave surface.
Another aspect of the present invention provides a damper assembly including a telescopic damper having a rod extending from a first end. A mounting means can be mounted on the rod and a dust tube is positioned on the damper, the dust tube including a substantially closed end, the closed end including contacting means formed thereon for contacting a bumper portion of the mounting means when the damper assembly contracts.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.